Field of the Invention
The invention relates to the field of crane hooks, gripping members engaging only the external or internal surfaces, and gripping members applying frictional forces, namely CPC B66C 1/34, 1/42, 1/422, and 1/44.
The Problem to be Solved
There are a large range of categories of lifting devices available on the market which can assist in material handling and transportation. One example is a mechanical claw that requires a driving force to open or close it. These are typically driven by rods or cylinders and powered pneumatically, hydraulically, or electrically (solenoids). These mechanical claws have the ability to open and close at any position but generally cannot operate (open and close) through the force of gravity. One limitation of such a design is that installing mechanical claw systems are complex and must be considered in the initial installation of crane-type equipment. The mechanical claws driven by pneumatics, hydraulics, or electrics require additional infrastructure and are difficult to quickly change. For example, gantry and bridge cranes require festoon systems to supply hydraulics or electrical power. Adding a drop for the claw driving source becomes an engineering challenge for incorporation into something like a wire rope hoist or gantry crane. This leads to the problem of being unable to easily change the gripping mechanism utilized by such a mechanical claw system. In a situation where objects of different sizes and shapes need to be moved, this can be a problem because it is unlikely that the initially installed mechanical claw has the versatility to lift a wide range of objects.
The industry does offer some aftermarket lifting devices which are intended to be compatible with equipment such as cranes (all types—floor, gantry, jib, etc.), hoists, winches, and trolleys and can be installed after the purchase of the crane or other material handling machine. However, the aftermarket lifting devices available still fail to offer the versatility necessary to grip a large range of dissimilar objects.
While working for a former employer, the inventor was involved in a safety incident investigation. Some irregularly cut pieces of titanium were being moved and rotated for their next cuts on a vertical hydraulic band saw. These pieces did not have much available room to use existing devices such as lifting tongs or scissor lifting clamps. The cut pieces often slipped out of these devices due to their irregular shape. The cut pieces of titanium would range from 20 lbs-45 lbs. Moving these pieces by hand was acceptable under OSHA safety standards. The cut edge of titanium is extremely sharp, and the worker was wearing cut resistant gloves as a safety precaution. The combination of sharpness, heft and irregular shape caused a cut piece of titanium to slide out of his hands, cutting through the glove and slicing his hand open from index to pinky finger, requiring stitches. The inventor was on the accident investigation team and was responsible for analyzing the causes of the incident and creating a corrective action plan that would reduce material handling risk in the future. The team discussed a lifting tong that grabbed a piece by more than two sides. After extensive search, the team could not find a product that suited their needs. The team made safety adjustments for the process, but was puzzled by the fact that there were no gripping devices similar to the lifting tongs available on the market, that could grip from three or more sides to accommodate irregularly shaped objects.